Method and means for beneficiating ores



United States Patent 6 Claims ABSTRACT OF THE DISCLOSURE A process for obtaining mineral values from ore froth flotation using a combination of reagents (1) an admixture of alkyl and alkenyl amine components wherein the amines contain long straight chain hydrocarbon groups and (2) an aromatic oil thus making it possible to obtain relative efiicient recovery over a substantially large temperature range.

This application is a continuation of application Ser. No. 486,217 filed Sept. 9, 1965, now abandoned.

The present invention relates as indicated to the benefication of ores and has more particular reference to the use of auxiliary flotation reagents for the froth flotation of various types of ores.

This is an improvement over my invention in my copending application Ser. No. 397,036 now Patent No. 3,341,135 filed Sept. 16, 1964.

There has been considerable activity in developing methods of concentrating potash ores. For instance, U.S. Patent No. 2,689,649 to Atwood relates to a process for concentrating potash ores such \as sylvite ore. As stated in the Atwood patent, problems arise when 150% of the ores utilized have a particle size larger than 40 mesh. In the Atwood patent the concept has been set forth that larger particle size sylvite ore may be concentrated employing froth flotation techniques by the inclusion of long chain !alkyl and alkenyl amine components. It was also stated in this patent that the usefulness of the amine compounds Was dependent upon temperature conditions at which the ore brine is concentrated and dependent upon the degree of saturation of the amine, i.e., the double bond equivalency as expressed by means of the well known iodine number. The higher the temperature of the brine, the higher must be the degree of saturation of the amine; While conversely the lower temperature ranges require higher unsaturation to maintain similar effectiveness.

In view of the requirement that the degree of saturation of the aliphatic portion of the amine must be varied in accordance with temperature, a constant surveillance is necessary to utilize that particular amine providing the greatest effectiveness at any given temperature. It will be appreciated that temperature conditions can change over a considerable range during a short period of time so that under ordinary circumstances it is necessary to continuously adjust the degree of saturation of the amine by altering the quantities of the various amines used. In other words, for instance, an amine having high unsaturation is mixed with an amine having low unsaturation to give a selected degree of saturation.

It will be quickly seen that one of the principal objects attendant the instant invention is the disclosure of a process to effectively float potash ores within a fairly wide temperature range without having to alter the degree of amine unsaturation in order to maintain maximum effectiveness of the flotation procedure.

Other objects of the present invention will appear as the description proceeds.

To the accomplishment of the foregoing and related ice ends, said invention then comprises the features hereinafter fully described and particularly pointed out in the claims, the following description setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principle of the invention may be employed.

Broadly stated, the present invention comprises the method of obtaining desired mineral values from ores by froth flotation, which comprises grinding said ore, pulping the ground ore, conditioning the resultant ore pulp with a flotation reagent comprising an admixture of a long chain aliphatic amine collector reagent and an aromatic oil as :an auxiliary reagent, subjecting said conditioned ore pulp to a froth flotation cell, and recovering said mineral values from said flotation cell.

From the foregoing broadly stated paragraph it will be seen that the present invention uses a combination of flotation reagents to condition the pulped ore soas to obtain the desired mineral values. The present admixture comprises as one component, long chain aliphatic amine collector reagents which are well known to those skilled in the flotation art.

The long chain aliphatic amine collector reagent is effective in selectively coating the particles to be floated, but only impart sufiicient hydrophobic characteristics to effectively bring about the flotation of approximately minus 14 mesh particles. However, by the addition of a quantity of an aromatic oil it is now possible to float by froth flotation substantially all of the desired material containing particles as large as 8 mesh.

As stated above, the amine collector reagents used in the present invention are the same as those used by ore refiners in prior flotation processes. These collector rea gents are long chain aliphatic amines consisting of from 8 to 22 or more carbon atoms and are most commonly prepared from beef tallow. They :are usually prepared as the salts of the amines, the most commonly used salt being the acetate, and they are purchased commercially as mixed aliphatic amine acetates. They contain generally about 70% primary amines with a chain length of C and 30% having a chain length of C In carrying out the invention, it has been found meritorious to float the coarse ore particles and the fine ore particles separately, or, if not floated separately, they are reagentized separately. The oil is preferably added to the coarse fraction. By coarse fraction is meant that fraction between about minus 6 and plus 20 mesh. The potash ore, after being deslimed, is split at 20 mesh. The two fractions are reagentized separately prior to being united for flotation, if this is desirable.

The auxiliary reagents applicable to the present invention are aromatic oils containing a high proportion of compounds having three and four rings in the molecule. These oils are especially suitable, as they have low pour points; also, viscosities stay low at low temperatures. It may be assumed that almost any mineral oil, aromatic or aliphatic, liquid at a fairly low temperature of operation, should be able to dissolve a fairly high saturated amine at such a low temperature and to disperse it. However, the aromatic oils are preferred.

In orderto illustrate the invention, the results with minus 20 mesh Carlsbad, New Mexico sylvite ore after suitable reagentizing are given below:

Similar eflicacious results are obtainable when operating with minus 20 mesh Canadian potash ore; as set forth below:

It has been shown that minus 20 mesh potash is floated successfully at low temperature (approximately 8 C.) with an alkylamine, heretofore stated to be adequate only at 25-35 C. (iodine number 10-15), if an oil is used as an auxiliary agent at the lower temperatures. Since the iodine number of the amine additive does not need to be changed, it can be readily seen that the present invention constitutes a pleasant unexpected discovery.

In the foregoing it has been shown that minus 20 mesh potash may be floated successfully at a fairly low temperature of approximately 8 C. with an alkylamine, usually adequate only at 2535 C., i.e. iodine number of 10-15, when an oil is employed as an auxiliary agent at the lower temperature. In other words an alkylamine having a higher iodine number does not have to be substituted for an alkylamine having a lower iodine number. While a relatively high temperature and relatively high saturated amine may have its useful range extended downwardly to a lower temperature by the addition of the aromatic oil, the converse is not true. For instance, a relatively low temperature and relatively low saturated amine of an iodine value of 48 does not have its effectiveness restored by including an aromatic oil when the froth flotation is carried out at 35 C.

The reason for this behavior is uncertain. A supposition is that the relatively unsaturated amines, at higher temperatures, not only lower part of their collecting power for potash; they also create over-frothing in the flotation cells, therefore, the amine is not absorbed on the potash surfaces but stays in solution. This, then, means that the relatively unsaturated amine employed has a relative high solubility at higher temperatures, a fault which cannot be corrected by the addition of oil.

On the other hand, the relatively higher saturated amines at lower temperatures form a white scum in the froth, indicating that solubility is extremely low. Under such circumstances, the amine cannot be absorbed on the potash surfaces and loses its collecting power. However, the oil utilized in the present invention dissolves the amine, disperses it in the brine and brings it in contact with the potash surfaces. Thus, the collecting power is restored. Due to its low solubility, the amine cannot be washed off the potash surfaces.

In the above discussion, primary concern was indicated relative the fine fraction '01: minus 20 mesh. In actual practice the coarse fraction, that is, minus 8 to plus 20 mesh, and the fine fraction, that is, minus 20 mesh, are floated together, even though the fractions may be reagentized separately.

It is already known in the art that approximately plus 14 mesh potash ore can only be efliciently floated by adding an auxiliary agent, such as an oil, at all times. It is also known, as stated in the above cited Atwood patent, to increase the iodine number of the amine as lower temperatures for froth flotation are employed. However, it is going against the prior art to deliberately replace a high iodine value amine at lower temperatures with a low iodine value amine and still retain efliciency of froth flotation.

Due to the general need for employing the oil as an auxiliary agent in coarse fraction flotation, it is not possible to undertake comparative tests with the coarse fraction as was carried out in the above in connection with the minus 20 fraction. However, the fact that a relatively high saturated amine is efiicient as a collector reagent for potash ore at relatively low temperatures in the presence of an aromatic oil may be shown and is unexpected whether it is for fine or coarse potash ore.

Results for coarse potash (minus 8 mesh to plus 20 mesh) floated at relatively high and relatively low brine temperatures employing a relatively high saturated amine in each instance are set forth below:

Brine Tailin gs Example temp., Iodine Oil grade,

0. number percent Carlsbad potash are (24% K20):

VII 25. 5 1015 Yes..." 0. 58 VIII 8.0 10-l5 Ycs 0.70 Canadian ore (24% K20):

IX... 22.0 10-15 Yes.. 0.79 X 8.0 1015 Yes. 1.04

Amine, Aromatic oil,

ton

of ore of ore Fine (minus 20 traction) 0. 05-0. 5 0. 05-1. 0 Coarse (minus 8 to plus 20 fraction) 0. 25-1. 0 0. 05-2. 0

It will be apparent that many changes and modifications of the several features described herein may be made without departing from the spirit and scope of the invention. It is therefore apparent that the foregoing description is by way of illustration of the invention rather than limitation of the invention.

I claim:

1. The method of obtaining desired mineral values from potash ores by froth flotation at a temperature range of between 8 C. to 20 C. which comprises grinding said ore, pulping the ground ore, conditioning the ore pulp with a flotation reagent comprising an admixture of alkyl and alkenyl amine components selected from the group consisting of primary aliphatic amines containing long straight chain hydrocarbon groups having 16 to 18 carbon atoms and their water soluble acid addition salts and having an average iodine value of between 10 to 15 which produces optimum results at a relatively higher temperature than said temperature range and further including a water immiscible aromatic oil containing a high proportion of compounds having 3 and 4 rings in the molecule to reestablish said optimum results at said temperature range, said aromatic oil being liquid at said temperature range and capable of solubilizing said amine, then subjecting said conditioned ore pulp to a froth flotation 'cell, and recovering said mineral values from said flotation cell, said cell being at a temperature of between 8 C. to 20 C.

2. The method of obtaining desired mineral values from potash ores by froth flotation at a temperature range of between 8 C. to 20 C. which comprises grinding said ore to at least 8 mesh, pulping the ground ore, separating the minus 8 mesh to plus 20 mesh fraction from the minus 20 mesh fraction, conditioning the minus 20 mesh fraction with a flotation reagent comprising an admixture to alkyl and alkenyl amine components selected from the group consisting of primary aliphatic amines containing long straight chain hydrocarbon groups having 16 to 18 carbon atoms and their water soluble acid addition salts and having an average iodine value of between to which produces optimum results at a relatively higher temperature than said temperature range and further including a water immiscible aromatic oil containing a high proportion of compounds having 3 and 4 rings in the molecule to re-establish said optimum results at said relatively lower temperature range, said aromatic oil being liquid at said temperature range and capable of solubilizing said amine, then subjecting said conditioned ore pulp to a froth flotation cell, and recovering said mineral values from said flotation cell, said cell being at a temperature of between 80 C. to C.

3. The method of obtaining desired mineral values from potash ores by froth flotation at a temperature range of between 8 C. to 20 C. which comprises grinding said ore to at least 8 mesh, pulping the ground ore, separating the minus 8 mesh to plus 20 mesh fraction from the minus 20 mesh fraction, conditioning the minus 20 mesh fraction with a flotation reagent comprising an admixture of alkyl and alkenyl a-mine components selected from the group consisting of primary aliphatic amines containing long straight chain hydrocarbon groups having 16 to 18 carbon atoms and their water soluble acid addition salts and having an average iodine value of between 10 to 15 which produces optimum results at a relatively higher temperature than said temperature range including a water immiscible aromatic oil containing a high proportion of compounds having 3 and 4 rings in the molecule to re-establish said optimum results at said temperature range, said aromatic oil being liquid at said temperature range and capable of solubilizing said amine, conditioning the minus 8 mesh to plus 20 mesh fraction with a flotation reagent comprising an admixture of alkyl and alkenyl amine components selected from the group consisting of primary aliphatic amines containing long straight chain hydrocarbon groups and their water soluble acid addition salts and having an average iodine value of between 10 to 15, thereafter re-combining said fractions, then subjecting said conditioned ore pulp to a froth flotation cell, and recovering said mineral values from said flotation cell, said cell being at a temperature of between C. to 20 C.

4. The method of claim 1 wherein the said cell is at a temperature of approximately 8 C.

5. The method of claim 2 wherein the said cell is at a temperature of approximately 8 C.

6. The method of claim 3 wherein thesaid cell is at a temperature of approximately 8 C.

References Cited UNITED STATES PATENTS 2,365,805 12/1944 C le 209.160 2,689,649 9/1954 Atwood 209l66 2,695,100 11/1954 Barr 209l66 3,059,774 10/1962 Wilson 209l66 3,265,211 8/1966 Ray 209l66 3,310,170 3/1967 Abernethy 209l66 HARRY B. THORNTON, Primary Examiner.

ROBERT HALPER, Assistant Examiner.

US. Cl. X.R. 24120 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,424,310 January 28, 1969 Martin Wilson It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 4, line 73, "admixture to" should read admixture of Column 5, line 13, "80 C. should read 8 C. Column 6, line 10, "80 C. should read 8 C.

Signed and sealed this 31st day of March 1970.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JR.

Commissioner of Patents Edward M. Fletcher, J r.

Attesting Officer 

